If I explain the way that I work, it might make more sense why I would think this feature would be useful. It is mostly a question of speeding up working.
Often there are more than one way of doing things - for example, in a high contrast scene, you could use tone equaliser / dynamic range compression / log tone mapping to try and compress the range of values.
So, I might want to try out a few different ways of doing something and compare them, so I will save a different snapshot let’s say for 3 different ways of doing it. I like to update each version and tweak it until I am happy with it. I will often hop between each version as I am doing this to update them. Then I will compare the final result of each version.
Currently, I have to type in a new name for the snapshot to keep track of what I am doing each time I hop between the version and update it, then either end up with a long list of snapshots, or delete some of the old ones. Although it is all easy to do, it does become time consuming after a while. So a quick button to update the version would speed things up. It is a bit like being to just save over a file with your latest version - it would be cumbersome if you always had to create a new file each time.
Maybe I am the only person that works like this, but let’s see what people think…